Search results for "absorption."
showing 10 items of 2682 documents
Cytosolic pH regulates root water transport during anoxic stress through gating of aquaporins.
2003
Flooding of soils results in acute oxygen deprivation (anoxia) of plant roots during winter in temperate latitudes, or after irrigation1, and is a major problem for agriculture. One early response of plants to anoxia and other environmental stresses is downregulation of water uptake due to inhibition of the water permeability (hydraulic conductivity) of roots (Lpr)2,3,4,5. Root water uptake is mediated largely by water channel proteins (aquaporins) of the plasma membrane intrinsic protein (PIP) subgroup6,7,8. These aquaporins may mediate stress-induced inhibition of Lpr2,4,9 but the mechanisms involved are unknown. Here we delineate the whole-root and cell bases for inhibition of water upta…
Oxygen transmittance correction for solar-induced chlorophyll fluorescence measured on proximal sensing: Application to the NASA-GSFC fusion tower
2017
Since oxygen (O 2 ) absorption of light becomes more pronounced at higher pressure levels, even a few meters distance between the target and the sensor can strongly affect canopy-leaving Solar-Induced chlorophyll Fluorescence (SIF) retrievals. This study was conducted to quantify the consequent error propagation and the impact of ignoring oxygen absorption effects on proximal sensing SIF measurements based on the O 2 -A absorption band with field-acquired and simulated data. It was demonstrated that the uncorrected oxygen transmittance between target and sensor distance of 10 m can lead to SIF relative errors ranging from 66% to higher than 100% when using a Spectral Fitting (SF) technique …
Antifungal and antimycotoxigenic activity of allyl isothiocyanate on barley under different storage conditions
2019
Abstract The present study evaluated the efficacy of allyl isothiocyanate (AITC) in avoiding the growth of Penicillium verrucosum and consequent ochratoxin A (OTA) production in barley during storage for 90 d. Environmental humidity was controlled using saturated salt solutions and moisture content (MC) of the grain was analyzed. Moreover, the residual concentration of AITC on stored barley was also examined. Samples with 20.6% of MC presented the highest absorption of AITC with levels ranging from 75 to 4 mg/kg at day 1 and 90, respectively. The population of P. verrucosum was significantly reduced after 24 h of AITC exposure. After 90 d, the non-treated control group reached a fungal popu…
The importance of thermal history: costs and benefits of heat exposure in a tropical, rocky shore oyster.
2015
Although thermal performance is widely recognized to be pivotal in determining species' distributions, assessment of this performance is often based on laboratory acclimated individuals, neglecting their proximate thermal history. The thermal history of a species sums the evolutionary history and, importantly, the thermal events recently experienced by individuals, including short-term acclimation to environmental variations. Thermal history is perhaps of greatest importance for species inhabiting thermally challenging environments and therefore assumed to be living close to their thermal limits, such as in the tropics. To test the importance of thermal history the responses of the tropical…
Conifer Needles as Thermoplastic Composite Fillers: Structure and Properties
2016
This study describes the properties of thermoplastic polymer composites based on polyethylene (of low and high density) and ethylene-propylene copolymers using various types of conifer needles (pine, spruce, fir, and cedar) as fillers. For the needles, thermogravimetric analysis (TGA) and TGA/Fourier transform infrared spectroscopy (TGA/FTIR) were performed to investigate their structures and thermal resistance, as required for the composite processing methods. Moreover, structural differences were studied for the analyzed fillers and composite materials (FTIR). The results were compared with the values obtained for composites with conifer wood flour. Composites with conifer needles (pine) …
Effect of Enzyme Amounts Used in Gastrointestinal Digestion Upon Solubility and Caco-2 Cell Uptake Assays of Minerals from Infant Formulas
2005
The effect of enzyme amounts used in gastrointestinal in vitro digestion upon the solubility and Caco-2 cell uptake of calcium, iron and zinc from infant formulas (IFs) was studied. Different amounts of enzymes (g enzyme/g IF), pepsin (0.002 and 0.048), pancreatin (0.0005, 0.002 and 0.01) and bile extract (0.003, 0.125 and 0.0625) were assayed. Mineral soluble contents and mineral uptakes by Caco-2 cells were affected by the enzyme amounts used in digestion. Although the highest mineral solubility (Ca 98.6 vs 46.2%; Fe 98.1 vs 83.9%; Zn 98.4 vs 83%) was obtained when the lowest enzyme (pepsin 0.002 vs 0.048; pancreatin 0.0005 vs 0.01g/g IF) and bile extract (0.003 vs 0.0625g/g IF) amounts …
NIR-absorbing transition metal complexes with redox-active ligands
2020
Bench top stable transition metal (M = Co, Ni, Cu) complexes with a non-innocent ortho-aminophenol derivative were synthesized by the reaction of metal(II)acetates with a ligand precursor in 2:1 ratio. The solid-state structures reveal the formation of neutral molecular complexes with square planar coordination geometries. The Co(II) and Cu(II) complexes are paramagnetic, whereas the Ni complex is a diamagnetic square planar low-spin Ni(II) complex. All complexes, and Ni(II) complex in particular, show strong absorption in the near-IR region. Peer reviewed
Enhancing the sound absorption of small-scale 3D printed acoustic metamaterials based on Helmholtz resonators
2018
Acoustic metamaterials have recently become of interest for their ability to attenuate sound by breaking the mass-density law. In this paper, acoustic metamaterials based on Helmholtz resonators and capable of attenuating sound up to 30 dB are fabricated for sound absorption applications in the small scale. The proposed metamaterials are subwavelength at a factor of $\lambda /12$ with respect to the lateral dimension of the units. The directional response due to the position of the acoustic source on the sound attenuation provided by the metamaterial is investigated by controlling the location of a loudspeaker with a robot arm. To enhance and broaden the absorption bands, structural modific…
Simultaneous Determination of Caffeine and Chlorogenic Acids in Green Coffee by UV/Vis Spectroscopy
2017
A simple method for the simultaneous determination of caffeine and chlorogenic acids content in green coffee was reported. The method was based on the use of UV/Vis absorption. It is relevant that the quantification of both caffeine and chlorogenic acids was performed without their preliminary chemical separation despite their spectral overlap in the range 250–350 nm. Green coffee was extracted with 70% ethanol aqueous solution; then the solution was analyzed by spectroscopy. Quantitative determination was obtained analytically through deconvolution of the absorption spectrum and by applying the Lambert-Beer law. The bands used for the deconvolution were the absorption bands of both caffein…
Physico-chemical properties and sensory profile of durum wheat Dittaino PDO (Protected Designation of Origin) bread and quality of re-milled semolina…
2018
To help future quality checks, we characterized the physico-chemical and sensory properties of Dittaino bread, a sourdough-based durum wheat bread recently awarded with Protected Designation of Origin mark, along with the quality features of re-milled semolina used for its production. Semolina was checked for Falling Number (533–644 s), protein content (12.0–12.3 g/100 g d.m.), gluten content (9.7–10.5 g/100 g d.m.), yellow index (18.0–21.0), water absorption (59.3–62.3 g/100 g), farinograph dough stability (171–327 s), softening index (46–66 B.U.), alveograph W (193 × 10−4–223 × 10−4 J) and P/L (2.2–2.7). Accordingly, bread crumb was yellow, moderately hard (16.4–27.1 N) and chewy (88.2–10…